Relationship between real-time ultrasound and carcass measures and composition in heavy sheep

Fat depth over the M. longissimus thoracis et lumborum (LL) at the 12th rib (USFat C) and the depth of the LL (USEMD) were measured before slaughter using a real-time ultrasound machine in 147 mixed sex, 22-month-old sheep of five genotypes. Equivalent measures were obtained on the carcasses (Fat C and EMD) and each carcass side was scanned by dual energy X-ray absorptiometry to provide an estimate of composition (percentage lean and fat). There was a significant (P < 0.001) correlation between USFat C and Fat C (fat depth over the LL at the 12th rib measured on the carcass) at r = 0.67. This was also the case for USEMD and EMD (muscle depth of the LL at the 12th rib measured on the carcass) with a significant (P < 0.001) correlation of r = 0.55. Liveweight per se was a poor predictor of Fat C and was of minimal value when used in combination with ultrasonic fat depth measurements. The prediction of Fat C was significantly underestimated by USFat C and this increased as the animals became fatter. The relationship between carcass and ultrasonic measurements of EMD was poor, but better when liveweight was used in combination with USEMD. The prediction of EMD was significantly overestimated by USEMD and this increased as the animals became heavier. Combining USFat C measurement with liveweight significantly (P < 0.001) improved the accuracy (R2) and precision (r.s.d.) with which either the percentage of fat or lean could be estimated. Measurement of USEMD was of no value for the estimation of the percentage of fat or lean. There was no significant (P > 0.05) sex effect on any of the relationships. Ultrasonic measurement of subcutaneous fat depth and muscle depth in heavy fat animals is subject to undefined error, but still provides a means to predict in vivo fat levels and muscle depth. However, the bias associated with the predictions suggest caution should be exercised when measuring heavy fat sheep and the need for further work to confirm the findings of the present study.

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Lamb carcass. 3. Describing changes in carcasses of growing lambs using real-time ultrasound and the use of these measurements for estimating the yield of saleable meat

Australian Journal of Experimental Agriculture ◽

10.1071/ea9960037 ◽

1996 ◽

Vol 36 (1) ◽

pp. 37 ◽

Cited By ~ 8

Author(s):

DL Hopkins ◽

DG Hall ◽

AF Luff

Keyword(s):

Real Time ◽

Linear Models ◽

Subcutaneous Fat ◽

Fat Tissue ◽

Sex Effect ◽

Poor Predictor ◽

Percentage Yield ◽

The Relationship ◽

Ultrasound Scanner

In experiment 1,76 cryptorchid (n = 37) and ewe (n = 39) lambs were scanned for GR (depth of muscle and fat tissue from the surface of the carcass to the lateral surface of the 12th rib, 110 mm from the midline) and M. longissimus thoracis et lumborum (LD) depth (USB) on 4 occasions over 3 months at intervals of 28 days with a real-time ultrasound scanner. Carcass GR measurements were obtained after the final live measure at 5.5 months of age. Significant (P<0.001) changes in GR and USB were detected as liveweight increased. All changes could be best explained by linear models (P<0.001) and there was a significant (P<0.001) sex effect evident for GR indicating that this is a useful measurement for monitoring changes in carcass fatness in live lambs. The correlation (r = 0.31) between ultrasonic and carcass GR was significant (P<0.05), however, mean ultrasonic and carcass measurements of GR were significantly different (P<0.05) for ewe, but not cryptorchid lambs. A sex effect was found with the relationship between in vivo GR, liveweight and carcass GR indicating that there was no significant relationship between GR measured ultrasonically and on the carcass when liveweight and sex were accounted for. In experiment 2, 86 ewe and 84 cryptorchid lambs were slaughtered in sex groups, the ewes at 6 months of age and the cryptorchids at 8 months of age. Before slaughter subcutaneous fat depth (USFat C) over the LD and LD depth (USB) were measured using a real-time scanner. Of the carcasses, 84 (42 ewes, 42 cryptorchids) were prepared into 'trim' lamb (TL) cuts. There was a significant (P<0.001) correlation between USFat C and the carcass equivalent (Fat C) for ewes and cryptorchids respectively (r = 0.63; r = 0.47). This was also the case for USB and carcass LD depth (B) with significant (P<0.001) correlations of r = 0.53 and r = 0.56 for ewes and cryptorchids respectively. Liveweight per se was a poor predictor of Fat C and B irrespective of measurement group and was of minimal value when used in combination with USFat C or USB measurements. The amount of variation in Fat C and B that was explained by the corresponding ultrasonic measurement and liveweight ranged from R2 = 0.29-0.39. Irrespective of the measurement group considered or the yield type, measurement of USFat C significantly (P<0.001) improved the accuracy with which percentage yield could be estimated over and above liveweight and increased the amount of variation (R2) in percentage yield that was explained. However, it is recommended that if ultrasonic measurements are to be used for predictive purposes, GR and LD depth be adopted.

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Changes in fat depths and muscle dimensions in growing lambs as measured by real-time ultrasound

Australian Journal of Experimental Agriculture ◽

10.1071/ea9930707 ◽

1993 ◽

Vol 33 (6) ◽

pp. 707 ◽

Cited By ~ 16

Author(s):

DL Hopkins ◽

KL Pirlot ◽

AHK Roberts ◽

AS Beattie

Keyword(s):

Real Time ◽

Subcutaneous Fat ◽

Carcass Characteristics ◽

Significant Error ◽

Adjustment Factor ◽

Inconsistent Result ◽

Ultrasonic Measurements ◽

Partial Correlations ◽

Ultrasound Scanner

Carcass characteristics of 3-4-month-old lambs from 2 experiments were measured with a real-time ultrasound scanner 4 times over 4 months. In experiment 1, all lambs grazed 3 pasture regimes consecutively over 4 months, and in experiment 2, 3 nutritional treatments were compared. Lambs contemporary to these, from a third experiment, were scanned before slaughter, and the equivalent carcass measurements obtained. Significant (P<0.001) changes in GR tissue depth, subcutaneous fat depth at the C site, and M. longissimus thoracis et lumborum (LD) dimensions were detected as liveweight increased with time in experiments 1 and 2. Depth of LD was found to increase more than width during the growth phase studied. High repeatabilities were obtained for GR, with partial correlations of 0.72 and 0.86, using liveweight as the adjustment factor. For fat depth, repeatabilities were moderate at 0.57 and 0.73, respectively. An inconsistent result was found for LD depth and width, with correlations of 0.68 and 0.29 for depth and 0.36 and 0.5 1 for width. In experiment 3, there were small differences between GR, fat depth, and the area of the LD muscle as measured in vivo and on the carcass, but the accuracy with which fat depth could be estimated from ultrasonic measurements for individual lambs was low compared with the GR measurement. Depth of LD measured in vivo was significantly (P<0.001) greater than on the carcass, but the converse was true for LD width, indicating a change in shape. Partial correlations between in vivo and carcass measures were 0.60 for GR, 0.17 for fat depth, 0.36 for LD depth, and -0.15 for LD width. For LD area, there was a range of 0.31-0.42 depending on the method used to determine area on the carcass. It was considered that real-time ultrasound offered potential when used to monitor changes in GR. Measurement of fat depth in lean lambs was subject to significant error and is not recommended. Of the muscle dimensions, LD depth offers potential, but repeatability may be unsatisfactory in lightweight lambs.

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Two-site evaluation of the relationship between in vivo and carcass dual energy X-ray absorptiometry (DXA) in pigs

Livestock Science ◽

10.1016/j.livsci.2006.05.025 ◽

2007 ◽

Vol 110 (1-2) ◽

pp. 1-11 ◽

Cited By ~ 7

Author(s):

A.M. Scholz ◽

A.D. Mitchell ◽

M. Förster ◽

V.G. Pursel

Keyword(s):

Dual Energy ◽

X Ray ◽

Site Evaluation ◽

The Relationship

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Genetic variation and relationship of ultrasonic measures and carcass composition in Suffolk cross lambs

Proceedings of the British Society of Animal Science ◽

10.1017/s1752756200593089 ◽

1996 ◽

Vol 1996 ◽

pp. 111-111

Author(s):

V.C. Flamarique ◽

R.M. Lewis ◽

G. Simm

Keyword(s):

Genetic Variation ◽

Selection Criteria ◽

Live Weight ◽

Ultrasonic Measurement ◽

Carcass Composition ◽

Selection Indices ◽

Terminal Sire ◽

Relationship Of ◽

The Relationship

Excess fat in lamb is regarded as an important reason for less lamb meat being purchased by consumers. This has encouraged the development and use (particularly in Terminal Sire breeds) of selection indices that can identify animals that will sire leaner progeny. These indices usually include live weight and in vivo predictors of body composition, such as an ultrasonic measurement of muscle and fat depth, as selection criteria (Simm and Dingwall, 1989). But the usefulness of such in vivo measurements as predictors of carcass composition depends on the correlation between, and the variation in, live and carcass measures. The objectives of this study were to determine the strength of the relationship between ultrasound and dissection measures of carcass composition, and the degree of genetic variation in these measures, in crossbred progeny of Suffolk rams.

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Accuracy of Measurements of Total-Body Soft-Tissue Composition by Dual Energy X-Ray Absorptiometry in Vivo

Human Body Composition ◽

10.1007/978-1-4899-1268-8_89 ◽

1993 ◽

pp. 381-383 ◽

Cited By ~ 2

Author(s):

Ole Lander Svendsen ◽

Jens Haarbo ◽

Christian Hassager ◽

Claus Christriansen

Keyword(s):

Soft Tissue ◽

Dual Energy ◽

Tissue Composition ◽

Soft Tissue Composition ◽

X Ray ◽

Accuracy Of Measurements ◽

Total Body

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A multi-center comparison of dual energy X-ray absorptiometers: In vivo and in vitro soft tissue measurement

European Journal of Clinical Nutrition ◽

10.1038/sj.ejcn.1600400 ◽

1997 ◽

Vol 51 (5) ◽

pp. 312-317 ◽

Cited By ~ 31

Author(s):

CD Economos ◽

ME Nelson ◽

MA Fiatarone ◽

GE Dallal ◽

SB Heymsfield ◽

...

Keyword(s):

Soft Tissue ◽

Dual Energy ◽

X Ray

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Reliability of in vivo neutron activation analysis for measuring body composition: Comparisons with tracer dilution and dual-energy x-ray absorptiometry

Journal of Laboratory and Clinical Medicine ◽

10.1016/s0022-2143(96)90058-x ◽

1996 ◽

Vol 127 (5) ◽

pp. 420-427 ◽

Cited By ~ 23

Author(s):

Kaizong Ma ◽

Donald P. Kotler ◽

Jack Wang ◽

John C. Thornton ◽

Ruimei Ma ◽

...

Keyword(s):

Body Composition ◽

Neutron Activation Analysis ◽

Activation Analysis ◽

Neutron Activation ◽

Dual Energy ◽

X Ray ◽

Tracer Dilution ◽

In Vivo Neutron Activation

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Using real-time ultrasound for in vivo assessment of carcass and internal adipose depots of dairy sheep

The Journal of Agricultural Science ◽

10.1017/s0021859620000106 ◽

2019 ◽

Vol 157 (7-8) ◽

pp. 650-658

Author(s):

J. Afonso ◽

C. M. Guedes ◽

A. Teixeira ◽

V. Santos ◽

J. M. T. Azevedo ◽

...

Keyword(s):

Real Time ◽

Prediction Models ◽

Linear Regression Analysis ◽

Subcutaneous Fat ◽

Live Weight ◽

Multiple Linear Regression Analysis ◽

Fat Content ◽

Fat Reserves ◽

Intermuscular Fat

AbstractFifty-one Churra da Terra Quente ewes (4–7 years old) were used to analyse the potential of real-time ultrasound (RTU) to predict the amount of internal adipose depots, in addition to carcass fat (CF). The prediction models were developed from live weight (LW) and RTU measurements taken at eight different locations. After correlation and multiple linear regression analysis, the prediction models were evaluated by k-fold cross-validation and through the ratio of prediction to deviation (RPD). All prediction models included at least one RTU measurement as an independent variable. Prediction models for the absolute weight of the different adipose depots showed higher accuracy than prediction models for fat content per kg of LW. The former showed to be very good or excellent (2.4 ⩽ RPD ⩽ 3.8) for all adipose depots except mesenteric fat (MesF) and thoracic fat, with the model for MesF still providing useful information (RPD = 1.8). Prediction models for fat content per kg of LW were also very good or excellent for subcutaneous fat, intermuscular fat, CF and body fat (2.6 ⩽ RPD ⩽ 3.2), while the best prediction models for omental fat, kidney knob, channel fat and internal fat still provided useful information. Despite some loss in the accuracy of the estimates obtained, there was a similar pattern in terms of RPD for models developed from LW and RTU measurements taken just at the level of the 11th thoracic vertebra. In vivo RTU measurements showed the potential to monitor changes in ewe internal fat reserves as well as in CF.

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